It is reported that high quality biodiesel named HiBD, which are the mixture of aliphatic hydrocarbons, can be obtained by catalytic cracking of oils and fats through decarboxylation reactions of triglycerides and fatty acids over MgO/SiO2 and MgO/carbon catalysts. In this study, in order to make clear effect of carrier materials and MgO loading several MgO catalysts were prepared using different type of carrier materials and loadings, and examined catalytic performance for HiBD production. Selectivity to hydrocarbons of diesel fraction increased with increasing specific surface area and volume of SiO2 support. Extent of the secondary cracking of the hydrocarbons generated was influenced by the particle size of SiO2; larger particle size inhibited the reaction. It is suggested that formation of ketones, as possible intermediates from fatty acids to hydrocarbons, should be suppressed over SiO2 supports with pore sizes smaller than 30 nm. Higher selectivity to the diesel fraction was obtained over carbon supported catalysts with higher specific surface area. Also higher decarboxylation activity was observable, which suggests that carbon support itself has the catalytic activity with different reaction mechanisms. Higher loading of MgO promoted the direct decarboxylation as well as ketone generation from the fatty acids, and the maximum selectivity to hydrocarbons and CO2 yield were obtained with a loading of 30 wt% over SiO2-supported catalysts.
In co-pyrolysis and co-gasification of sludge and coal, understanding characteristics and reactivity of feedstock and its char is necessary in these processes, because the pyrolysis of feedstock and gasification reaction of its char act each other complicatedly. In this work, characteristics and reactivity of chars produced from single feedstock and both samples by pyrolysis under various atmosphere were evaluated. As results, it was shown that there was different characteristic in chars by difference of pyrolysis atmosphere and way of blending samples. And starting gasification reaction temperature and reaction behavior of chars produced by different conditions were different. The pore structure of chars produced from both samples was different from that of chars produced from single sample, and that was different by conditions of blending and co-pyrolysis atmosphere. It was considered that steam gasification behavior was changed by difference of pore structure of char.
The present study analyses the employment effects of 12 different power generation technologies using renewable energy resources from a life cycle perspective. Employment characteristics of these technologies are quantitatively revealed by estimating direct and indirect employment creation using the Renewable EnergyFocused Input-Output (REFIO) model the authors developed. The use of the REFIO model allows for the consistent comparison of employment characteristics among all the renewable power generation technologies. The analysis finds that each of the 12 different technologies has unique features. The life cycle employment potential ranges from 1.01 to 5.04 person-year/GWh depending on the types of technologies. In addition, the employment potential is estimated by location (i.e. domestic or abroad). It should be noted that wind and photovoltaic power generation technologies indirectly create more employment opportunities abroad than other technologies. Furthermore, the present study examines not only the quantity of jobs created but also their quality. While each technology requires skilled workers for tasks that is distinctive of that technology (e.g. well drilling for geothermal, plant operation for wood biomass), a wide range of jobs in service sectors (e.g. legal work, finance and accounting, transportation) are created in common with all the technologies.
Waste plastic pellets are one of important materials as an alternative fuel to COG (Coke Oven Gas) in CaCO3 calcination furnaces. However, the amount of waste plastic is limited. So possibility of waste wood utilization was investigated and the pellets combining waste plastic and waste wood were developed. To clarify the combustion behavior of the pellets, a lab-scale test and a commercial furnace injection test were conducted. The burn-out time at 1000 ℃ of combined pellets (6 mmφ), with ratios of 10, 20 and 30wt% waste wood, was around 25 s. This time was the same as that for conventional waste plastic pellets. The combined pellets with a ratio of 10wt% waste wood were injected into a commercially operating calcination furnace. The amount of heat input from COG and combined pellets was reduced by 5% as compared with that of COG alone. This result was the same as that for conventional waste plastic pellets. This effect was caused by combustion of the pellets close to CaCO3 in the calcination furnace. These results show that combined pellets with a ratio of 10wt% of waste wood can be used as an alternative fuel to COG as conventional waste plastic pellets.